The purpose of this research is to learn about the basic principles involved in the interactions among cell surface receptors. The proposed research will study the mechanism and specificity of the interaction between the human leukocyte CD2 and CD58 cell surface adhesion receptors, using modern NMR spectroscopy and genetic engineering. Human leukocyte cell surface receptors are responsible for many biological processes such as cell adhesion, cell signaling and cell recognition, which are important in development, immune responses, tumor metastasis and wound healing. Our initial research will focus on the NMR structure determination of the adhesion domain of human CD58 receptor. Mutational studies of human CD2 and CD58 receptors will be carried out to study the binding site and binding specificity of the CD2/CD58 interactions, along with the NMR structure determination of the complex between the adhesion domains of CD2 and CD58. This research study will increase our understandings in immunology and cell biology, and lead potentially to the discovery of drugs that can be used in disease control by affecting specific binding activities of cell surface receptors.